1. Field of the Invention
This invention relates to a magnetic disk drive, particularly to a magnetic disk drive wherein, with respect to outer dimensions of a slider of a magnetic head included as part of the magnetic disk drive along with a magnetic disk and a head supporting device, a thickness from a flying plane to an opposite surface on the reverse side thereof is determined to be 0.65 mm or less, a length thereof in the direction of air discharge to be 3 mm or less, or preferably 0.5 to 3 mm and a width in a direction orthogonal to the direction of air discharge to be 2.5 mm or less, or preferably 0.5 to 2.5 mm. Therefore, it is possible to achieve miniaturization, a high capacity and a high density for the magnetic recording medium, and a smaller diameter of the magnetic disk with high durability and high stability thereof.
2. Discussion of the Background
In a conventional magnetic disk drive, a magnetic head is used which flies by dynamic pressure caused by running a magnetic disk opposed thereto and maintaining head clearance due to a minute air bearing generated between the magnetic disk and the magnetic head. A flying-type magnetic head has a basic structure including reading/writing elements formed on a slider having flying planes on the side of a surface thereof opposing a magnetic disk. As conventional examples, a Winchester-type magnetic head provided with a U-shaped core having a coil at a slider composed of a magnetic body and a composite-type magnetic head attached with a bulk-type reading/writing element in a groove of a slider composed of a nonmagnetic ceramic structure and a thin film magnetic head formed with thin film reading/writing elements on a slider thereof by a process similar to the semiconductor production technology, are well known.
Among these flying-type magnetic heads, the Winchester-type magnetic head and the composite-type magnetic head are publicly known, for instance, by Japanese Examined Patent Publication No. 569/1982 (U.S. Pat. No. 3,823,416), Japanese Examined Patent Publication No. 21329/1983, Japanese Examined Patent Publication No. 28650/1983 or the like. The reading/writing elements are the bulk-type ones provided with coils composed of wires wound around cores.
The thin film magnetic head is publicly known, for instance, by Japanese Examined Patent Publication No. 84019/1980 (U.S. Pat. No. 4,190,872), Japanese Unexamined Patent Publication No. 84020/1980 (U.S. Pat. No. 4,219,854) or the like. The thin film magnetic head is provided with a structure wherein a thin film magnetic film, a conductive coil film, an inter-coil-layer insulating film, a protection film and the like are formed on a slider. With respect to the thin film magnetic head, the inductance value of the conductive coil film is low compared with a bulk-type flying magnetic head, by a single digit or more. Accordingly, the high frequency characteristic thereof is extremely good and the thin film magnetic head has excellent high response performance and is suitable for the high density recording. Owing to this characteristic, the thin film magnetic head can achieve a high speed in data transfer and a high density of magnetic recording in a domain which cannot be reached by the bulk-type flying magnetic head.
Furthermore, the thin film magnetic head is provided with characteristics wherein a magnetic film constructing a magnetic circuit thereof is composed of a metallic magnetic material of permalloy or the like having a high saturation magnetic flux density and a high permeability, a magnetic gap length thereof can be reduced, and a pole width for reading and writing that can be extremely narrowed down. Accordingly, in addition to the excellent high frequency characteristic wherein the inductance value of the conductive coil film and the magnetic film composing a core is low, the thin magnetic head can achieve an excellent high frequency response performance and high recording density compared with the bulk-type flying magnetic head.
Next, explanation will be given of a specific example of the flying-type magnetic head in reference to FIG. 20. FIG. 20 is a perspective view of a conventional magnetic head, wherein a reference numeral 1 designates a slider composed of, for instance, a ceramic structure, and 2, a reading/writing element.
The slider 1 is formed to have two rails 101 and 102 spaced apart from each other on a plane thereof opposing a magnetic disk and the surfaces of the rails 101 and 102 are formed with flying planes 103 and 104 having a high flatness.
With respect to the outer dimension of the slider 1, as shown for instance in U.S. Pat. No. 4,624,048, normally, a thickness d from each of the flying planes 103 and 104 to an opposite surface on the reverse side 105 is selected to be 0.85 mm, a length L in the air discharge direction is selected to be 4 mm and a width w in a direction orthogonal to the air discharge direction is selected to be 3.2 mm. The flying planes 103 and 104 are provided with structures wherein tapered portions 103a and 104a each is provided on the side of an end thereof which makes an inflow end for an air flow that flows in the direction of an arrow mark xe2x80x9ca,xe2x80x9d generated in the combination thereof with a magnetic disk.
The reading/writing element 2 is a thin film element formed by a process similar to the IC production technology in case of a thin film magnetic head, which is attached to an end portion of the air discharge on the opposite side of the tapered portions 103a and 104a. Although not illustrated, the Winchester-type magnetic head, or the composite-type magnetic head is a bulk-type one provided with a coil wound around a core.
When the reading/writing element 2 is composed of a thin film element, with respect to the dimension of the reading/writing element 2, to satisfy a required electromagnetic conversion performance, a diameter D2 thereof in a direction orthogonal to the air discharge direction is determined to be approximately 0.3 mm, and a diameter thereof D1 in a direction from the flying planes 103 and 104 to the opposite surface 105, approximately 0.4 mm. Furthermore, the thin film magnetic head is provided with take-out electrodes 201 and 202 on a side end face of the slider 1 attached with the reading/writing elements. These take-out electrodes 201 and 202 communicate to a conductive coil film of the reading/writing element 2, not shown. The take-out electrodes 201 and 202 are portions to which lead wires communicating to the magnetic disk drive are connected. To provide a lead wire connecting area, a length L0 thereof in a direction orthogonal to the air discharge direction xe2x80x9caxe2x80x9d is determined to be about 0.5 mm, and a wire width h1 viewed in the direction of the opposite surface 105 to the flying planes 103 and 104, approximately 0.2 mm.
The above thin film magnetic head is produced utilizing a high accuracy pattern forming technology, such as photolithography, by forming a great number of thin film reading/writing elements on a wafer to be transformed into a portion of the slider 1, by separating the thin film reading/writing elements obtained by performing a cutting operation on the wafer, and by performing a necessary grooving operation on the rails 101 and 102 or the like and polishing the flying planes 103 and 104.
The magnetic disk drive is attached with the above magnetic head on a front end portion of a head supporting device an end of which is supported by a positioning device that positions the magnetic head on predetermined tracks of the magnetic disk and drives the magnetic head by a so-called contact-start-stop (hereinafter CSS) system wherein the flying planes 103 and 104 of the slider 1 contact the surface of the magnetic disk by a spring and starting and stopping thereof are performed in the contact state. Thus, when the magnetic disk is stationary, the flying planes 103 and 104 are pressed to the surface of the magnetic disk by spring pressure. When the magnetic disk rotates, as shown in FIG. 21, a dynamic lift is generated at the flying planes 103 and 104 including the tapered surfaces 103a and 104a of the slider 1, and the magnetic head flies at a flying height xe2x80x9cgxe2x80x9d wherein the dynamic pressure caused by the dynamic lift balances with the spring pressure xe2x80x9cPxe2x80x9d of a gimbal. The conventional magnetic head having the above dimensions is provided with a stable flying performance in a domain having a flying height of 0.3 xcexcm or more.
The magnetic disk drive of this kind is utilized in combination with a computer and to meet a requirement of data processing of the computer system, should correspond to the higher density and the higher capacity of the magnetic recording and the downsizing of the magnetic disk diameter.
However, as noted above, the magnetic head utilized in the conventional magnetic disk drive is provided with dimensions wherein the thickness d thereof is selected to be 0.85 mm, the length of L in the air discharge direction is selected to be 4 mm and the width w in a direction orthogonal to the air discharge direction is selected to be 3.2 mm. Therefore, the following problems arise.
(a) To achieve a high recording density, a head spacing loss should be minimized by lowering the head flying height. However, the conventional magnetic head of the above-noted dimensions experiences a high value of a rolling angle. Accordingly, the effective flying height can not be lowered under a value determined by this rolling angle.
FIG. 22 is a diagram for explaining the rolling angle xcex2 generated between a magnetic disk M and the magnetic head. The larger the rolling angle xcex2, the larger the difference between the flying height xe2x80x9cg1xe2x80x9d viewed from the inner peripheral rotating side and a flying height xe2x80x9cg2xe2x80x9d viewed from the outer peripheral rotating side. Normally, in the magnetic disk drive, a magnetic conversion element 2 on the outer peripheral rotating side of the magnetic head is utilized. Therefore, even when the flying height xe2x80x9cg1xe2x80x9d on the inner peripheral rotating side thereof is reduced, so far as the rolling angle xcex2 remains large, the flying height xe2x80x9cg2xe2x80x9d on the outer peripheral rotating side thereof which directly influences on the electromagnetic conversion performance, cannot be reduced. Accordingly, in the conventional magnetic head which is limited with respect to the lowering of the rolling angle xcex2, the high density recording which can be achieved by lowering the effective flying height and by reduction of the spacing loss, is also limited. Furthermore, the rolling angle xcex2 has a tendency such that the larger a relative speed between the magnetic disk and the magnetic head is, the larger the rolling angle is. Accordingly, the more the magnetic head is placed towards the outer periphery of the magnetic disk, the effective flying height increases as does the spacing loss. Therefore, the desired higher density recording cannot be achieved.
(b) Since the rolling angle xcex2 is large, the flying posture of the magnetic head becomes unstable and a head crash is liable to occur. Accordingly, the reliability thereof is lowered.
(c) As a means of solving the above problems caused by the increase of the rolling angle, a method may be considered wherein a center of motion of the slider, that is, a pivot position of a gimbal, is set to a position deviated from the middle of the slider. However, in this case, a deviation of mass is caused with respect to the center of motion of the slider, the moment of momentum becomes nonuniform, and a follow-up performance to vibration thereof is deteriorated. As stated above, in the magnetic head having the conventional dimensions, it is difficult to lower the flying height while stabilizing the flying posture and maintaining reliability.
(d) When the magnetic head is placed stationary on the magnetic disk, the landing area occupied by the magnetic head can not be diminished under an area determined by the length in the air discharge direction of L=4 mm and the width of w=3.2 mm in a direction orthogonal to the air discharge direction. Accordingly, the magnetic recording area which is substantially usable on the magnetic disk is limited by the landing area of the magnetic head, which causes limitations in increasing the track number and increasing the recording density and the recording capacity. This shortcoming is especially and significantly displayed relative to a small magnetic disk. The factor which directly influences the reduction of the track number is the width w, and the conventional magnetic head having the width w as large as 3.2 mm is an obstacle to increasing the number of tracks.
(e) To meet a requirement of downsizing a computer as in a laptop personal computer or the like, the magnetic disk drive per se should be downsided. However, as the conventional slider has a thickness d as large as 0.85 mm, this is a limitation in thinning the magnetic disk drive. Furthermore, as the number of magnetic disks which can be accommodated in the space of the magnetic disk drive is limited by the thickness of the magnetic head, there is a limitation in enhancing the capacity of the magnetic disk drive by increasing the number of disks.
(f) To meet a requirement of portable handling of a computer, the magnetic disk drive should have excellent portability. To provide excellent portability, it is most desirable to drive the magnetic disk drive by a cell. However, in the conventional magnetic head provided with the above-mentioned dimensions, there is a technical difficulty in obtaining a driving torque for a disk driving motor to rotate the magnetic disk stably by using a cell, due to overcoming the static friction of CSS starting.
(g) In the thin film magnetic head, since the area of the end face thereof in the air discharge direction attached with thin film reading/writing elements 2 is a large area determined by the thickness of d=0.85 mm and the width of w=3.2 mm, the spacing or a pitch interval between the thin film reading/writing elements 2 is increased and the number of elements which can be formed in a wafer is decreased. Accordingly, the cost of the thin film magnetic head is raised.
It is an object of the present invention to solve the above conventional problems and to provide a method of maintaining constant flying height of a magnetic head and a magnetic disk drive utilized therefor, which is suitable for the higher density and the higher capacity of the magnetic recording and the downsizing the magnetic disk diameter and excellent in durability and stability.
According to a first aspect of the present invention, there is provided a method of maintaining a constant flying height of a magnetic head on a magnetic disk substantially constant irrespective of a change of a skew angle comprising the steps of:
rotating the magnetic disk;
providing a slider with flying planes on a side thereof opposing the magnetic disk, with a thickness from each of the flying planes to an opposite surface on a reverse side thereof in a range of 0.30 to 0.65 mm, with a length in a first direction of air discharge thereof in a range of 1.2 to 2.8 mm, and with a width in a second direction orthogonal to the first direction in a range of 1.0 to 2.3 mm, said slider being further provided free of any transverse pressurization contours, slider rolling compensation grooving, or other slider rolling compensation elements on any portion thereof;
attaching a magnetic head at the air discharge end of the slider, said attached magnetic head including reading/writing elements arranged on a first side and an opposite second side of the air discharge end of the slider,
providing a head supporting device configured to support the slider and attached magnetic head at a first end thereof by attachment to a middle position of the slider in a manner that does not deviate a center of motion of the slider and does not provide rolling compensation relative to the slider and attached magnetic head;
providing a positioning device configured to support a second end of said head supporting device opposite to said first end at a pivot point in a manner that does not provide rolling compensation relative to the slider and attached magnetic head;
rotating the magnetic disk; and
pivoting the first end of the head supporting device relative to the second end thereof supported by the positioning device at said pivot point to thereby move said slider with the attached magnetic head at the first end thereof above said rotating magnetic disk with the first side of the sir discharge end of the slider being oriented in a direction toward the center of the magnetic disk while the opposite second side is oriented in a direction toward the outer periphery of the magnetic disk, said slider movement relative to the rotating magnetic disc being along an arcuate path that establishes a different skew angle between a longitudinal direction of the slider and a tangent of said magnetic disk relative to different radial magnetic disk locations;
wherein the reading/writing element arranged on the first side of the air discharge end of the slider undergoes a first amount of separation from the rotating magnetic disk and the reading/writing element arranged on the opposite second side of the sir discharge end of the slider undergoes a second amount of separation from the rotating magnetic disk that is greater than said first amount of separation due to the slider rolling when said slider with the attached magnetic head is moved above said magnetic disk to said different radial locations associated with different skew angles, with the difference between the second amount of separation and the first amount of separation determining the flying height of the slider and attached magnetic head above the magnetic disk, said flying height not changing more than 0.02 xcexcm when the flying height is set to be 0.1 xcexcm and the skew angle is changed in a range of xe2x88x9220 to 20 degrees without providing slider rolling compensation relative to the slider and attached magnetic head or any of the structure moving or supporting the slider and attached magnetic head.
According to a second aspect of the present invention, there is provided the method of maintaining the flying height of the magnetic head according to the first aspect of the invention, further comprising providing the magnetic disk with a diameter approximately within a range of 1.8 inches to 5.25 inches.
According to a third aspect of the present invention, there is provided the method of maintaining the flying height of the magnetic head according to the first aspect of the invention, wherein
the diameter of the disk is 2.5 inches or shorter; and
the disk is in a shape of circle without a hole in the center thereof.
According to a fourth aspect of the present invention, there is provided the method of maintaining the flying height of the magnetic head according to the first aspect of the invention, wherein
the slider is of a negative pressure type.
According to a fifth aspect of the present invention, there is provided the method of maintaining the flying height of the magnetic head according to the first aspect of the invention, wherein
the diameter of the disk is 2.5 inches or shorter;
the disk is in a shape of circle without a hole in the center thereof;
the slider is of a negative pressure type; and
the number of the magnetic head and the number of the magnetic disk are one.
According to a sixth aspect of the present invention, there is provided magnetic disk drive comprising:
a magnetic disk;
a disk support configured to support said magnetic disk;
a drive mechanism configured to rotate said disk support and said magnetic disk supported thereby;
a slider configured to have flying planes on a side thereof opposing the magnetic disk, with a slider thickness from each of the flying planes to an opposite surface on a reverse side thereof being 0.30 to 0.65 mm, with a slider length in a first direction of air discharge thereof being 1.2 to 2.8 mm, and with a slider width in a second direction orthogonal to the first direction being 1.0 to 2.3 mm, said slider further being configured to be free of any transverse pressurization contours, slider rolling compensation grooving, or other slider rolling compensation elements on any portion thereof;
a magnetic head attached at the air discharge end of the slider and having reading/writing elements arranged on first and second apposite sides of an air discharge end of the slider;
a head supporting device configured to support the slider at a first end thereof coupled to a middle position of the slider so as to not deviate a center of motion of the slider and in a manner that does not provide rolling compensation relative to the slider and attached magnetic head; and
a positioning device configured to support a second end of said head supporting device opposite to said first end at a pivot point and being configured to pivot the head supporting device around the pivot point to move the head supporting device above said rotating magnetic disk in a manner that does not provide rolling compensation relative to the slider and attached magnetic head with the first side of the air discharge end of the slider being oriented in a direction toward the center of the magnetic disk while the opposite second side is oriented in a direction toward the outer periphery of the magnetic disk, said slider movement relative to the rotating magnetic disc being along an arcuate path having an arc determined by a length of the pivoting head supporting device, said arc determining a different skew angle between a longitudinal direction of the slider and a tangent of said magnetic disk relative to different radial locations of the slider with attached magnetic head over the magnetic disk;
wherein the reading/writing element arranged on the first side of the air discharge end of the slider undergoes a first amount of separation from the rotating magnetic disk and the reading/writing element arranged on the opposite second side of the air discharge end of the slider undergoes a second amount of separation from the rotating magnetic disk that is greater than said first amount of separation due to the slider rolling when said slider with the attached magnetic head is moved above said magnetic disk to said different radial locations associated with different skew angles, with the difference between the second amount of separation and the first amount of separation establishing a flying height of the slider and attached magnetic head, with said flying height being maintained at about 0.1 xcexcm with changes to the flying height of the slider and attached magnetic head being 0.02 xcexcm or less when said slider with the attached magnetic head is moved above said rotating magnetic disk to said different radial locations associated with different skew angles without providing rolling compensation relative to the slider and attached magnetic head or any of the structure moving or supporting the slider and attached magnetic head.
According to a seventh aspect of the present invention, there is provided the magnetic disk drive according to the sixth aspect of the invention, wherein
each of the reading/writing elements is a thin film element.
According to an eighth aspect of the present invention, there is provided the magnetic disk drive according to the sixth or seventh aspect of the invention, wherein each of the flying planes is a plane having no tapered portion at an air inflow end thereof.
According to a ninth aspect of the present invention, there is provided the magnetic disk drive according to the sixth aspect of the invention, wherein said positioning device is configured to pivot and move the slider to radial locations over the magnetic disk that correspond to skew angles in askew angle range of xe2x88x925 to 20 degrees.
According to a tenth aspect of the present invention, there is provided the magnetic disk drive according to the sixth aspect of the invention, wherein said positioning device is configured to pivot axed move the slider to radial locations over the magnetic disk that correspond to skew angles in a skew angle range of xe2x88x9220 to 20 degrees.
According to an eleventh aspect of the present invention, there is provided the magnetic disk drive according to the tenth aspect of the invention, further comprising configuring the magnetic disk to have a diameter approximately within a range of 1.8 inches to 5.25 inches.
According to a twelfth aspect of the present invention, there is provided the magnetic disk drive according to the sixth aspect of the invention, wherein the diameter of the disk is 2.5 inches or shorter and the disk is in a shape of circle without a hole in the center thereof.
According to a thirteenth aspect of the present invention, there is provided the magnetic disk drive according to the sixth aspect of the invention, wherein the slider is of a negative pressure type.
According to a fourteenth aspect of the present invention, there is provided the magnetic disk drive according to the sixth aspect of the invention, wherein the diameter of the disk is 2.5 inches or shorter;
the disk is in a shape of circle without a hole in the center thereof;
the slider is of a negative pressure type; and
the number of the magnetic head and the number of the magnetic disk are one.
It has been found that the slider having the dimensions wherein the thickness from each of the flying planes to the opposite surface is 0.65 mm or less, the length in the air discharge direction is 3 mm or less, or preferably 0.5 to 3 mm, and the width in a direction orthogonal to the air discharge direction is 2.5 mm or less, or preferably 0.5 to 2.5 mm, has high flying stability while maintaining a low flying height. This is because, compared with the conventional magnetic head, the rolling angle (or rolling value) is considerably reduced exceeding a predictable range. Moreover, as shown later in actual measurement data, the lowering of the rolling angle is especially remarkable at the outer peripheral side of the magnetic disk wherein the skew angle is large. Accordingly, at the outer peripheral side of the magnetic disk having a large skew angle, which essentially necessitates the lowering the rolling angle, the increase of the effective flying height and the increase of the spacing loss are restrained, thereby achieving higher density recording.
In this application, since the selection of the configuration of the slider is performed as a means of reducing the rolling angle, the alteration in the center of motion of the slider or the like in not necessary. Accordingly, there are no problems of the deviation of mass with respect to the center of motion of the slider, the nonuniformity of the moment of momentum or the like, and therefore, the flying height can be reduced while stabilizing the flying posture and providing reliability.
Furthermore, as shown in actual measurement data infra, it is found that a constant flying height can be maintained without being influenced substantially by the size of the skew angle. As means of maintaining the flying quantity constant without being influenced by the size of skew angle, there are inventions disclosed, for instance, in Japanese Unexamined Patent Publication No. 278087/1986, U.S. Pat. Nos. 4,673,996, and 4,870,519. The sliders disclosed in these prior arts, are provided with shallow grooves on the side faces of rails, which are called a transverse pressure contour slider (TPC). In this application, the flying height is maintained constant without being influenced by the size of the skew angle by the selection of the dimensions of the slider and not by the grooving operation of the slider. Therefore, the invention is provided with an advantage wherein the TPC grooving of a slider is not necessary.
Furthermore, since the constant flying height can be maintained without being influenced substantially by the size of skew angle, it is possible to adopt a zone bit recording system. Therefore, a magnetic disk drive having a high density recording and a high capacity can be obtained. Furthermore, since the constant flying height can be maintained without being influenced substantially by the size of the skew angle, the skew angle can be set at a large value, thereby miniaturizing the magnetic disk drive.
Furthermore, since the width in a direction orthogonal to the air discharge direction is 2.5 mm or less, compared with a slider having a conventional magnetic head, the landing area occupied by the magnetic head on the magnetic disk when the magnetic head is placed stationary on the magnetic disk is considerably reduced. Accordingly, the number of tracks on the magnetic disk is increased, which contributes to the increase of the recording density and the memory capacity thereof. This operation is significantly effective particularly in a magnetic disk having a small diameter.
Since the thickness d of the slider is 0.65 mm or less, the magnetic disk device can be thinned by 70% or less of the conventional device. Furthermore, the number of magnetic disks which can be accommodated in the magnetic disk drive, is increased, thereby achieving a higher capacity thereof.
When the thickness d from each of the flying planes to the opposite surface on the reverse sides exceeds 0.65 mm, the position of the center of gravity thereof is shifted on the side of the opposite surface which is a plane connecting to a gimbal, thereby deteriorating the flying stability. When the thickness is too thin, the rigidity of the slider is lowered, torsion or deformation thereof is caused in the slider and the flatness of the air bearing plane can not be provided. Accordingly, the thickness d is set to a lower limit value which can provide the flatness of the necessary air bearing plane, in a range of 0.65 mm or less. Furthermore, when the length L and the width w are too small, a flying plane area sufficient for securing stable flying performance may not be provided, thereby deteriorating the flying stability. Accordingly, the lower limit values of the length L and the width w are preferably 0.5 mm or more.
Furthermore, by the miniaturization of the total configuration of the slider, the dynamic lift is reduced and accordingly, the spring pressure can be lowered. Therefore, the loading force exerted between the flying plane and the magnetic disk in contacting the magnetic head to the magnetic disk is lowered and therefore, friction and wear are diminished thereby promoting the durability thereof.
Furthermore, since the static friction in the CSS starting, is reduced, the driving torque of the disk driving motor is decreased thereby reducing the power consumption. Since the disk driving motor consumes most of the power for the total of the magnetic disk drive, the power consumption of the total of the magnetic disk drive is reduced, thereby realizing a magnetic disk drive capable of driving the device by a cell.
Compared with the slider in the conventional magnetic head, the total configuration is miniaturized and particularly in the thin film magnetic head, the area of the end face of the slider to be attached with the reading/writing elements is decreased. Accordingly, when the reading/writing elements are formed by thin film elements, the number of the reading/writing elements which can be formed in a wafer is increased thereby contributing significantly to cost reduction.
Furthermore, by the weight reduction thereof in accordance with the selection of dimensions thereof, the following operations can be provided.
First, compared with the slider in the conventional magnetic head, the mass of the slider can be significantly reduced. Therefore, the resonance frequency of a head-gimbal system is increased and crashing is eliminated even when using a low flying height of 0.2 xcexcm or less thereby promoting CSS reliability.
Further, by the reduction of the mass thereof, the load applied to an actuator for accessing is reduced and high speed accessing can be performed. Especially, in case of the thin film magnetic head, to the inherent performance wherein the inductance value of the conductive coil film is low, the high frequency performance is excellent and the high speed response performance is excellent, the high speed accessing is synergetically multiplied, thereby dramatically elevating the reading/writing speed and the data transfer speed.